Dome lighting fixture



July 1, 1952 R. e. NORDQUIST DOME LIGHTING FIXTURE '2 SHEETS-SHEET 1 Filed March 13, 1948 D/SFFUS/NG INVENTOR. Ziobert GA/migamzf y 1, 1952 R. G. NORDQUIST 2,602,135

DOME LIGHTING FIXTURE Filed March 13, 1948 2 SHEETS-SHEET 2 INVENTOR.

/ Babe/'2? 6/1 01 4115216 Patented July 1, 1952 ,DOMELIGHTING FIXTURE Robert G. Nordquist, Glen Ellyn, 111., ,assignor :to iBat-ent License Corporation, Chicago, I ll,, a

f i corporationcfzlllinois ,All fi al i iniMa ifi 11 Claims; (01. 240-135) This invention deals merits inaj'lensed lighting fixture adapted to proiecta directed, strongly;intensifiedbeam of light onto a predetermined reading' or equivalent area o'r,z,one and, more particular into a fixture of this type which is also ,adaptedto disseminate a ,difiused, jflood light illumination laterally of the ,intensificd'rbeam.

Previous lighting fixturesfdesigned to emit through aims at relatively-intensebeam directly enerally with improveing fixture made up. oia lightwtransmissive panel illuminating. a] given area-such, for example, as I I .-a reading planebeneath the :fixt'ure, have, in vmost cases the disadvantage that thesurround- 'ingflareas or zones are subjected to undesirable lateral glare, occasioned by direct -viewability of the filament .or other light source of the fixture from such areas. "In the eventlight controlling means such as louvers, special'lensing, or reflectorsand the like are employed-tolimit the direct ,rays emanating {from "the source; then the total light available jromgand-the efiicieh'cy of the fixture are. substantially-cut sewn? Moreover; the

adaptability and utility era given-fixture, as for installation in more than one surrounding, are

.severely restricted;andthese'various -expedients still do notoflerEadesirableeaseofcontrol'.

The above objection as to side-glare is =par. ticularly marked when the installation of=the'fix- :tures is intended *for a public, multi-passenger vehicle, in which it is desirable to illuminate surrounding zones other than the beam-illuminatedar'ea, ;for example, an aisle zone: orcertain car-card areas, with a 'so'iter, =more diffused :type

of "illumination. PasSengersjin -the :aisle or occupying seats-adjoining the beam-lighted area, though they are main-beam through the fixture lens', :are still invariably annoyed by being exposed to a direct view ofathe beamsource.

e Other-practical objectionjsto existing fixtures of this general- 'class arise-from the bulk or complexity, the expensivene ssandthe' lackof adaptability of {the "various louver", bracket, connector and other econstituent elements-which must 'be employed'in association with the lens and light not impinged direotlyhy the source thereof if an attempt .is -110 be "made to- 1 achieve'an'y degree cinch-glare illumination. A simple, inexpensive' fixture which dispenses with the aforesaid auxiliary pompoiients and affords the desired SOI't fJf illumination hasyet to be offered-thetrade' It is thereforea general object of the invention tto provide afixture,;primar ily composed of a one- -;piece-;li ght transmissive panel including a clear portion or -aflens and having -=a light source and 1948, Serial No, 14,112 Y component :thermore; in which itrisimpossibleate-obtain a ditributes materially-tattle intensi projected ,by *theifiXtll-re J 'further eclear iportion 3413 0111 zj urroundingnsaid element in ano el an u arelation thereto, therebyzservin I to .-a vclean-direct beam emitting p -..ther clear portion integral :said. beam remitting rportion novel inclined :or'. conical :rel

reflector within said :p .1161, inwhieh said ens or clear portion isiso'relateditovthenfcmainder 9f said'paneliand to :said reflector to directpnto a predetermined area-a 'beam-ofeliehi; ir enstituted by a componentldirect 'fromlsaidusource nd, a PreflectecL-by said ;:re,f l'ector; and, fur.-

rect view of said light source ;from-1=a ny;-;point outside said predetermined, zbeamli hted-are :It is :armore specificobjectftoprovide a light.-

and an internal light source andreflectorrwllerein'said panel-includes a clear or condensing ,lens portion and Ban adjacent .clear, transparent portion so related-.to the afirstxnamed: portionand reflector that the li ht, source :is :Subiect 1130 xiireet viewsonly throughithe :fi-rst' namediclearor lens portion, notwithstanding the -=f act that :said

adjacent clear portion :is fully exposed :to the source andrin transmitting zrefleetedeiieht; iconor, tithe beam 'A still r further-fobjec, "is:tpa;pro.vid a ,fixture of the type described; 1i.-n c.1u nee some o illum nation, a reflector andeazoneeeiecezlieh et anfi missive panel enclosing said source andzreiiector, wherein,saidpanellincludesac iano+ccnvex,..clearbeami prevent direc t ou h said fu hereleer :;from' any rpprtion: of; the

viewing of said ,source portion-end, fin rturn,

.tot'al zone illuminated bygsaid; fixture, gotherrthan that which is Joear illu,:minated' throu h ai element. a Yet another object is to provide a fixture of the foregoing .characterui-n which the-beam emitted 1 through; theco,

tral e1.ear el mentsefath panel is intensifiedebyrrays of; light reflected rpm the reflector and dnwhieh -said reflected ,raysglare restricted, in traversing :the panel .for this inurpose, to said eclear portion adj dining the recomemitting element, :thereb y 'resultingin :vastly improvedlight'controlu T Another specific .object of the invention eisaito :provide *a' novel light-i-transmissive epanel; for a lighting fixture of the-type described, includ n ortion;and;L f-

' last inamed rportion 15 ,efiectiveito :prevent :pxit

therefrom of direct rays f;rom-; leud, e

ter-

a v 1 traversing :the seam tics and relationships, in which the panel is a simple, one-piece member which is free from bulky, light control means, which is extremely versatile in its adaptability to various installations and which achieves a maximum of lighting efficiency in operation.

Other objects of the invention will be apparent to those skilled in the art upon a consideration of the following specification and by reference to the accompanying drawings, in which:

Fig. 1 is a view in transverse vertical section through a'fixture in accordance with the present invention, illustrating structural'details of the light-transmissive panel thereof-and its'relation to a'source ofillumination and reflector with which it coacts;

Figs. 2 and 3 are fragmentary views in transverse verticalsection taken'respectively at right angles to one another showing the method of mounting the fixture of the invention in sealed relationship toa curved vehicle'deck or other supporting surface with which it is associated;

Figs. 4, and 5 are, respectively, fragmentary schematicviews'in longitudinal side elevation and front elevation illustrating a proposed installation of a system of the fixtures according to the invention in a conventional type of elongated public vehicle such as a railway or trolley car, bus, airplane or the like, and showing the improved illumination of the interior of such vehicle made possible by the system; and

Fig. 6 is a bottom plan view of the fixtureof the invention, in accordance: with a preferred embodiment thereof.'

The lighting fixture of the present invention, although particularly intended for installation in vehicle lighting systems, i. e., in buses, railway and trolley cars, airplanes, etc., is also well adapted for more general application in lighting systems of other types in which, as stated above, it is desired to obtain an intensified and wellcomplicated and dust-catching auxiliary controlled beam "of light from an internal light 7 source or filament, accompanied by a lateral diffused illumination of the space surrounding said beam. I

'While I have chosen to illustrate the fixture (as in Fig. 6) in a circular external outline, characterized by concentric, circular, clear lens and adjoining zones and a, surrounding peripheral diffusing zone, it is to be understood that the specific external shape of the fixture in this regard is not of controlling importance, and that the principles of the invention are equally adaptable to structures having other external outlines.

' The advantages afforded by the present'structure are primarily traceable to the novel lighting panel thereof and its relationship to an internal reflector and light source.

Y The panel itself involves a novel relationship of a central, preferably plano-convex clear lens element a surrounding, clear, inclined area and an external diffusing area, the inclination of said first named area relative to said lenselement being such that direct light rays from said source which impinge 4 said clear area, externally of the lens, do so in an endwise direction, almost parallel to its length, and are transmitted therethrough without exiting from said clear area, for final emission through said diffusing area. This result is due to the fact that said rays can only impinge the opposed inner surfaces of the'cleararea at anangle less than that minimu'mangle which will permit exit through said area. Consequently, it is absolutely impossible for one located outside of the zone of direct beam-illumination by the fixtures lens element to view the light source.directly., As a further consequence of this, intense sideglare such as is frequently at source of annoyance to surrounding vehicle pas-- sengers is completely eliminated; yet at the sametime, the clear area surrounding the lens is available for the transmission, and mergence with the lens beam, of rays reflected from a reflector behind the light source, thereby greatly augmenting and intensifying the final reading beam at the desiredzone to bev direct-illuminated.

Referring to Fig. 1 of the drawings, wherein the basic structural aspects of the fixture are most clearly illustrated, particularly the crosssectional; outlineof the light transmissive component thereof and its novel relation to a light source and reflector, the reference numeral. Hi designates the fixture generally. The latter includes a specularrefl'ector ll having ,a socket; tube l2' swaged therein centrally thereof. This; tube is adaptedito fixedly receive a conventional. bayonet-type'socket 13in whichthe lighting: element I4, illustrated as a conventional "moan-- descent filament .bulb; is received. It will be: understood from the description to follow that the invention .is notneces sarily limited to such filament-typeelementor to a point light source, and thatother types of lightingmeans, such as a gaseous discharge or arctype are contemplated.

I4'as alight source, on the. understanding that saidsource wil l find its equivalentin the light emissive gas, the .electrode orother conventional light emissi-ve -element of whatever other'type of illumination'is applied to the fixture. V

The reflector ,l lis provided with an integral surrounding annular rim or flange H which. may have a hinge l6 secured marginally thereto for 'pivotally supporting an annular ornamental. bezel or like panel carrying frame 17.. The latter may be secured to the reflector flang II by means of a screw l8 threaded into a tapping pad 19 aflixed to said flange. e 1 The reference numeral '20 denotes the circular light transmissive panelof the fixture, the peripheral flange M of whichis supported by frame IT, in the opening .22 of,the latter. The cross-sectional outline of this panel is of material importance'in the invention and will hereinafter be discussed in detail. An annular. sponge rubber orfelt cushion 23, preferably cemented to' thereflector flange ll'- concentrically of the reflector, is adapted to be compressed between said flange and theupper surface of the panel flange 2| so as to dust-seal the interior of the fixture in a very effective manner. V

' The light: transmissive panel 20 comprises a central, plano-convex, clearlens portion 24, a

' surrounding, inclined or conical portion 25 which tIOII'Of a vlight source mounta light source .7 and iswe'll adaptedto be molded with requisite accuracy by massproduction'methods. It involves no complicated louvers, special .lensing, connectors, brackets, etc. 1

Reference has been made'to the special adaptability of the fixture 'for'use'in bus, railroad,

airplane or like lighting systems; It will be apparent to those skilled in the art that the basic principle thereof is also applicable quite generally in the field of space lighting, for example, in headlights, searchlights, etc., and, in fact, in practically any beam-lighting installation in which it is desired to' control side glare and still maintain full lighting 'efliciency; e I I-cIaim:

11 A fixture of the type described, comprising a hollow, dished, light transmissive panel and a shaped "reflector fixedly. associated with said panel whereby to provide'a space for the reception of a light source therebetween, means-to mount alight source in s'aid's'pace, said panel defining the forward extremity of said fixture and including a'clear, beam-emitting element located forwardly of and in axial alignment with said source anda further annular tapered, clear sec-y tion integral with and laterally merging with said element, saidclear sectionbeing defined by tapered external surfaces "of smooth, uninterrupted characterfdivergingoutwardly from said beam emitting element and forwardly away from.

said space at an angle relative to the axis'of the fixture through; said reflector, light source and beam-emitting element' such that direct rays from said source laterally entering said clearsection impinge the internal surfaces thereof at a.

reflective angle smaller than the angle of exit, said clear section being transparent throughout so as topa'ss rays reflected from said reflector andimpinging the external surface of the sectionhearestsaid reflector.

21 A fixtureof the type described, a hollow,

comprising dished; light transmissive panel and a shaped reflector fixedly associated with said panel whereby to provide'a space for the reception of a lightsource' therebetween, means to mount alight source in said space, said panel defining the forwardextremity of said fixtureand including a clear, beam-emitting element located forwardly of and in axial alignment with said source and a further clear section integralwith and laterally merging with said element, said clear section being defined by tapered external surfacesof smooth, uninterrupted'character diverging. outwardly from said beamemitting elementand forwardly away from said space at an angle relative to the axis of the fixture through said reflector, light source and beam-emitting element such that direct rays from said source I laterally entering said clearsection impinge the internal surfaces thereof at a reflective angle smaller than the angle of exit, said clear section being transparent throughout so as to pass rays reflected from' said reflector and impinging the external surface of theseetion nearestsaid reflector; said'reflector being-so disposed relative to said source and panel asto reflect, rays from said source to the clear section only of said panel.

3. A fixture of the type described, comprising a hollow, dished,.light transmissive panel and a shaped reflectoryfixedly associated with .said panel :whereby to providea space "for the receptherebetween, means to in said space, said paneldefining the forward extremity of said fixture. and

including a clear, beam-emitting element located 8 forwardly of, andin axial alignment with said source and a further clear section. integral with andlaterally' adjoining said element, and a diffusing section integral with and merging with sad clear section, said clear section being dee fined by tapered external surfaces of smooth, uninterrupted. character diverging outwardly from said beam emitting element and forwardly away from said space at anangle relative to the axis of the fixture through saidreflector, light source and beam-emitting elementsuch that direct rays from said source entering said clear section from a lateral direction impinge the internal; surfaces thereof at an angle smaller than the angle of exit, said clear section being transparent throughout so as to passraysreflected from said reflector and impinging the external surface of the section nearest said reflector, said reflector being so disposed relative to said source and panel as to reflect rays from said source :to

the clear section .only of said panel, said diffusing section being located relative tosaid clear section to emit in diffused form said rays internally traversing said clear section and reflected .from said internal surfaces thereof.

4. A lightingfixture comprising a reflector and a hollow, drum-like, light;transmissive "panel fixedly connected-to said reflectorg means to ,mount a light source in thespace betweensaid the periphery of said-beam-emitting portion, the

forward and rear surfaces of said clear section being disposed about said beam emitting portion in a generally conical shape diverging. radially upwardly of said beam-emitting portion .and in an axialv direction away. from said ,lightsource,

said clear section being definedby smooth, un-

interrupted surfaces and being-transparent :to rays externally impinging the-same, the inclination of said clear section relative to said beamemitting portionbeing suchthat; theangle of impingement of-its internal surfaces by direct light rays from said source laterally entering and longitudinally traversing the-same is not substantially in excess of the exit angle, whereby said rays are-reflected internally in-said clear 7 section in longitudinallytraversing thesame,

said clear section being positioned relative to saidreflector for transmission of reflected .rays

from said source in convergent relation to a beam traversing said lens portion. g

5. A-lighting, fixture comprising a reflector and a hollow, drumlike,- light transmissive panel fixedly connected. to said reflector, means to mount a light source in the space between said reflector and panel, said panel definingthe forward extremity of. said fixture and including a ;central, plane-convex, clear, beam emitting lens portion located forwardly of the light source, an

annular clear 'sectionmerging directly with the periphery of said lens portion, the forward and rear surfaces of said clear section being disposed about said beam emittinglens portion in a, generally conical-shape diverging radially outwardly of said beam-emitting portionand in an. axial direction away from said light? source, said clear sectionbeingtransparent to rays externally impinging the same, and an external annular light diffusing section merging directly with 'said last named; section, the

inclination-of said clear section relative to said lens portion being such that 9 the angle of impingement of its internal surfaces by direct light rays from said source laterally entering and longitudinally traversing the same is not substantially in excess of 42, whereby said rays are reflected internally of said clear section in longitudinally traversing the same,

said clear section being positioned relative to said reflector for transmission therethrough, to the exclusion of said lens portion, of reflected rays from said source directing said reflected rays in convergent relation to a beam emitted by said lens portion, said diflusing section being located, relative to said clear section to emit in diffused form said internally reflected direct rays.

6. A lighting unit comprising a shaped reflector, a light transmissive panel in fixed relation to said reflector and means to mount a light source between said reflector and panel, said panel defining the forward extremity of said unit and having a clear beam-emitting section located immediately forwardly of and in axial alignment with said source and a clear, annular, rearwardly and inwardly inclined section surrounding and merging with the external periphery of said beam-emitting section and fully transparent to rays externally impinging the same, the angle of inclination of said annular section relative to the axis of said light source and first named section being in inverse ratio to the distance of said light source from said beamemitting section and being of a value such that direct rays from said source entering and internally traversing said inclined section impinge the internal surfaces of the latter at angles less than the angle of exit, said clear, inclined section being defined by opposed smooth, uninterrupted surfaces. I

7. A lighting unit comprising a shaped reflector, a light transmissive panel in fixed relation to said reflector and means to mount a light source between said reflector and panel, said panel defining the forward extremity of said unit and having aclear beam-emitting section located immediately forwardly of and in axial alignment with said source and a clear, annular, rearwardly and inwardly inclined section surrounding and merging with the external periphery of said beam-emitting section and fully transparent to rays externally impinging the same, the angle of inclination of said annular section relative to the axis of said light source and first named section being in inverse ratio to the distance of said light source from said beamemitting section and being of a value such that direct rays from said source entering and internally traversing said inclined section impinge the internal surfaces of the latter at less than a 42 angle, said beam-emitting and inclined sections being disposed relative to said reflector whereby rays reflected from the latter pass only through said inclined section.

ROBERT G. NORDQUIST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 869,548 Cobham Oct. 29, 1907 1,235,297 Dillon July 31, 1917 1,393,573 Ritter Oct. 1-1, 1921 1,657,502 Harrman Jan. 31, 1928 1,888,995 Matter Nov. 29, 1932 2,192,019 Schepmoes Feb. 27, 1940 r 2,244,737 Stewart June 10, 1941 2,337,794 Arenberg Dec. 28, 1943 FOREIGN PATENTS Number Country Date 502,544 England Mar. 20, 1939 

